1. Field
The present disclosure relates to an image display device including a plurality of micro light-emission elements that are minute light-emission elements, and a display.
2. Description of the Related Art
An image display device that includes a plurality of micro light-emission elements that constitute a pixel and that are provided on a driving circuit substrate is suggested. For example, in Japanese Unexamined Patent Application Publication No. 2002-141492, a small image display device that displays a color image by forming a driving circuit on a silicon substrate, arranging a minute ultraviolet light-emission diode (LED) on the driving circuit, and disposing a wavelength conversion layer converting ultraviolet light into visible light of red, green, and blue is disclosed.
Such an image display device has characteristics of small size, high brightness, and high durability. Thus, the image display device is expected to be used for a glass-type terminal such as an augmented reality (AR) glass-type terminal (refer to U.S. Patent Application Publication No. 2013/0070338) or a display such as a head-up display (HUD). In addition, an image display device in which organic electroluminescence (EL) is deposited as a light-emission layer on a silicon substrate in which a driving circuit is formed is already in use. However, there is room for improvement in terms of brightness and durability.
The display such as the glass-type terminal or the HUD superimposes light from an outside world with light from the image display device by a combiner device. By doing so, the image formed by the image display device can be displayed in a superimposed manner on a scenery of the outside world to an observer. An imaging optical system, which projects the image formed by the image display device on the eyes of the observer, is disposed between the image display device and the combiner device. In order to use the light emitted by the image display device effectively, the imaging optical system has to converge the light emitted by the image display device as much as possible. For example, in a case where an imaging optical element of the imaging optical system is a lens, the aperture of the lens has to be increased. In addition, in a case where the imaging optical element of the imaging optical system is a curved reflection mirror, the diameter of the reflection mirror has to be increased. In order to increase the amount of convergence, the size of the imaging optical system has to be increased. In a case where the imaging optical system is increased, the sizes and weights of the glass-type terminal or the HUD are increased and it is not preferable for the observer.
In order to use such a display comfortably, the display has to be light and small. However, it is not easy to realize small and light display with superior characteristics such as higher brightness and longer operation time by effectively using the emitted light of the image display. That is, for the image display device including the plurality of micro light-emission elements, effective usage of emitted light without increasing the size of the imaging optical system is desired.
It is a purpose of this invention to provide an image display device including a plurality of micro light-emission elements, which enables effective use of emitted light without increasing the size of an imaging optical system, and also to provide a display with such a an image display device.